੩ㇺᄢቇ㒐ἴ⎇ⓥᚲᐕႎ ╙ภ$ ᐔᚑᐕ᦬ Annuals of Disas. Prev. Res. Inst., Kyoto Univ., No. 48 B, 2005

Deformation Monitoring and Exploration on Shuping Landslide Induced byImpoundment of the Three Gorges Reservoir, ChinaFawu WANG, Gonghui WANG, Kyoji SASSA, Kiminori ARAIBA*, Atsuo TAKEUCHI**,Yeming ZHANG***, Zhitao HUO***, Xuanming PENG***, Weiqun Jin**** National Research Institute of Fire and Disaster, Japan** Natural Groundwater Research Institute, Japan*** Yichang Institute of Geology and Mineral Resources, China Geological Survey, ChinaSynopsis
The Three Gorges Dam construction on the Yangtze River in China is the largest
hydro-electricity project in the world. After the first impoundment in June 2003, many landslides
occurred or reactivated. Shuping landslide is one of the most active landslides among them. In thispaper, the deformation of the Shuping landslide monitored by GPS, extensometers, and crack
measurements are summarized. Also, for the investigation of the groundwater situation, 1m-depth
ground temperature measurement was conducted, and the groundwater veins were estimated.
Based on the monitoring data and exploration results, a deformation model of the landslide caused
by impoundment of reservoir was proposed.
Keywords: landslide, displacement monitoring, reservoir impoundment, groundwaterRiver in China is the largest hydro-electricity project in1. Introduction
the world. The dam site is located at Sandouping village
The Three Gorges Dam construction on the Yangtze
near Maoping town, the capital of Zigui County, HubeiFig. 1 Location map of the Shuping landslide and Qianjiangping landslide in Three-Gorge water reservoir area,Hubei Province, ChinaProvince. The designed final dam height is 185 m, thefinal length 2309.5 m, and the designed final highest
water level 175 m. When dam construction is finished,
the Three-Gorge Reservoir will reach Chongqing City,
about 660 km upstream from the dam. The first
impoundment started from 95 m on June 1, 2003, andreached 135 m on June 15, 2003. As soon as the waterlevel reached 135 m, many slopes began to deform andsome landslides occurred (Wang et al. 2004). For
example, in the early morning at 00:20 July 14, 2003,
Qianjiangping landslide occurred in Shazhenxi town (Fig.

1) at the bank of Qinggan-he River, a tributary of theYangtze River (Zhang et al. 2004). Direct economic
losses caused by the landslide were about 7 million USD,
and the asset value of Shazhenxi town was reduced by40%. Twenty-two boats and ships were damaged andsunk in Qinggan-he River and the Yangtze River.
Although a warning was announced by the local
government based on precursory deformation of theslope two hours before the final failure, 13 people on theslope, and 11 fishermen on boats in the nearby river werekilled.

Fig. 2 Shuping landslide consisting of two blocks at the main stream of the Three Gorges Water Reservoir

Fig.3 Plane of the Shuping landslide and locations of monitoring and measurement works

From the above example, it is very clear thatmonitoring of landslide deformation is very urgent in thisimportant area, and time prediction of landslide
occurrence based on the monitored data and field
investigations are fatal issues for the safety of dam
structure and human activity in the Three Gorges area. It
is also a good field to monitor the landslide deformation
caused by impoundment of reservoir, because the waterlevel changing in the reservoir is in the largest scalearound the world.
For these reasons and aiming to study the influenceof impoundment on landslide deformation, we selected
Shuping landslide, which is located at the main stream ofthe Yangtze River (Fig. 1) in Shazhenxi Town, just about
3.5 km from the Qianjiangping landslide, as our research
and monitoring field. Figure 2 is an oblique photographof the Shuping landslide, and Figure 3 is the plane of thelandslide. The landslide ranged its elevation from 65 m
to 500 m. Its width was about 650 m, the estimatedthickness of the sliding mass was 40 m to 70 m
according to the bore hole data, and the total volume wasestimated as 2.0 u 107 m3. The toe part of the landslide
was under the water level of the Yangtze River. The
slope is gentle at the upper part and steep at the lower
part with a slope angle of 22 degrees and 35 degrees
respectively..
2.

Features of the Shuping landslide

The Shuping landslide is an old landslide which
consists of two blocks. This can be confirmed in thephotograph (Fig. 2). After the first impoundment of theThree Gorges water reservoir ended on June 15, 2003,
obvious deformation phenomenon appeared at the slope,and it became intense from February 8, 2004. Also, thetwo blocks shows different deformation rate at slope
surface. The serious deformation situation made 580
inhabitants and 163 houses in danger directly, and all of
the inhabitants were asked to live in the disasterprevention tents which were provided by the central
government. Until May 2004, most inhabitants moved
their houses out of the landslide area.
Figure 4 shows a crack at the right boundary of
Block-1 outcropped at a local road. The right-hand sideis the sliding mass consisting of red muddy debris of oldlandslide, and the left hand side is bedrock of sandy
mudstone, muddy siltstone of Badong formation ofTriassic period (T3b).

Figure 4 Deformation situation at the right boundary of
Block-I outcropped at a roadside

Figure 5 Muddy water seeped out of the toe part of theShuping landslide (downstream side of Block-I)
Figure 5 shows muddy water coming from Block-1.
It appears at the river even at continual sunny days
showing no relationship with surface water erosion, but
the underground water erosion from the inner part of thelandslide.
3.

Slope deformation characters of the Shupinglandslide

Because the landslide area is a densely populatedarea and its intense deformation occurred just after theoccurrence of the Qianjiangping landslide, thedeformation situation was observed by the inhabitants
and reported to the local government promptly.
According to the urgent investigation report (Gan et al.
2004), the typical deformation behaviors were recorded
as follows.
From the end of October to the beginning of November

200Extension

D4aD4b100

D550

J3J2b0

D6a-50-2000J5D6b-100-150

J1D1bConstraction
10203040Days from February 12, 2004

4.

GPS monitoring results

Two GPS monitoring lines were arranged at thecentral longitudinal section of the two blocks by China
Geological Survey. Each monitoring line has three GPS
monitoring points, i.e., ZG85, ZG86 and ZG87 from toeto upper part in Block-I, and ZG88, ZG89 and ZG90
from toe to upper part in Block-II (See Fig. 3). Themonitoring started in July 2003, just one month after thefirst impoundment. The measurements were conducted
one time each month by Rockfall and Landslide
Research Institute of Hubei Province.
Figure 7 shows the monitored results of the GPS
monitoring at the first six months after the impoundment.
The displacement rate of Block-I increased rapidly after
October 2003, and other two tendencies are also veryclear. (1) The displacement at the lower part is larger
than that at the upper part, this may be caused by waterbuoyant of the impoundment of the reservoir; (2) The
displacement of Block-I is more active than Block-II,
showing that the two blocks are independent from eachother.

50Displacement of GPS monitoring points (mm)Deformation of cracks (mm)150

deformation occurred at the other parts in the landslide
block. For the 50 days period from February 24, 2004,
the maximum displacement including extension andcontraction respectively reached about 140 mm, showing
an active deformation.

Figure 6 Measured results of crack deformation in
Block-I
Because of the serious deformation situation, local
government decided to monitor the cracks distributing inthe slope from February 12, 2004. The inhabitants wereasked to measure the width change of the cracks near
their houses (see Fig. 3). For measurement, two smallpiles were set across a crack, and the distance between
the two piles was measured three times one day. Figure 6
shows a part of the measured results of the cracks.
However, because the inhabitants are moving out of thisarea, the measurement points are decreasing gradually.
Roughly, the measurement results of the crack
deformation shows that the extension behavior occurredat the boundary and inside landslide, and contraction10080

downslope

ZG88
ZG86
ZG85

60

40

ZG87

20

ZG89
ZG90

㩷

2003: Cracks became obvious at the slope surface,especially at the upper part. These cracks wereenlarged from January to February 2004.
On January 5 and February 8, 2004: The water at the toepart of the landslide became very muddy. FromMarch, the muddy water appears almost everyday.
Figure 5 shows the muddy water situation in April
2004. This phenomenon is a very dangerous signfor slope deformation, because it may mean that thenewly sheared soil at the sliding surface was erodedby underground water gradually.
On January 25 and February 8, 2004: Sharp noises
coming from underground were heard by theinhabitants at night for two times. The noise ispossibly caused by shearing at the sliding zone.

02003-7-1

2003-8-31 2003-10-31 2003-12-31
Monitoring date

Figure 7 GPS monitored results along the central sectionlines of Block-I and Block-II5.

Installation of extensometer and the monitoringdisplacement rate exceeds 2mm/hour, a warning will beannounced.

Figure 8 Extensometer installed in Shuping landslide
The deformation is recorded on the rolled paper (left)
and also saved in a memory (right box)

020403052

Shuping-extensometer-start-2005-1-1452

20

Displacement (mm)16552
52

10160

15552
52
5215052
52
52
52
145

0-1052
-20

water level in Three Gorges at damsite-30
Aug. 7

Sept. 1 Sept. 30
2004

Oct. 30

Nov. 28

Water level (m)Rainfall (mm)results
Until April 2004, the displacement monitoring of the
Shuping landslides included crack measures conducted
three times each day, and the GPS monitoring conducted
one time each month. However, because of theevacuation of the inhabitants, the crack monitoring wasinterrupted gradually. Located at the main stream of theYangtze River, it is not enough for the Shuping landslide
to be monitored only with GPS. Although GPS
monitoring has high precision, the time interval ofmeasurement is too large. Facing this situation, twoextensometers donated by Kowa Co. LTD., a Japanesecompany were installed in the Block-I of the Shupinglandslide in April 2004. The extensometer isSakata-Denki style. The monitoring can continue for one
week or one month automatically. A warning system isalso connected with the extensometer. When the52 140

135
Dec. 28
Jan. 26|2005

Figure 9 Monitored results of the extensometers (middle), the precipitation data in Yichang City (top) and water level in
the Three Gorges Dam site (bottom)

The automatic monitoring with the extensometer wasconfirmed to be working well (Zhang et al. 2004).
However, two extensometers are not enough for such alarge landslide. In August 2004, another 11
extensometers were installed along the central line of thelongitudinal section of Block-1, with emphasizing on theserious deformation parts. Also because of the limit offunds, the extensometers cannot form a continual
longitudinal section line.
Figure 8 shows the extensometer installed in Shupinglandslide. The positions of all of the thirteen
extensometers were shown in Figure 3 as “SP1-x”.
Among them, SP1-1 and SP1-2 were set across the main
scarp; from SP1-3 to SP1-6 were set below the Shahuangroad which has a high traffic. SP1-7 and SP1-8 were set
almost parallel with SP1-5 and SP1-6. SP1-9 was set atthe low part. Then, SP1-10, SP1-11, and SP1-12were set
near the Yangtze River at the toe part of the landslide.
SP1-13 was set at the right boundary of Block-1 shownin Figure 4, because the crack extension is obvious.
Figure 9 is the monitoring results of all the thirteen
extensometers, companying with the water level in theThree Gorges at dam site showing at the bottom, and therainfall records of this area showing at the top.
The monitoring results show some tendencies of thelandslide displacement. (1) The SP1-1 and SP1-2 at themain scarp did not record obvious displacement. One
possible reason is that the setting positions of the twoextensometers did not cross the main scarp. (2) The
deformations at SP1-5, SP1-6, SP1-7 and SP1-8 are themost active ones. (3) The toe part of the landslide shows
compression behavior. Comparing with the largest
displacement at the lower part by GPS monitoring in thefirst six months after the first impoundment, it may
estimate that the toe part moved down faster at the first

period and became silent now; the upper part moved
slowly at the first stage, and now followed the movementof the lower part and compressed the lower part. An
exact examination will be conducted with thecomparison of the recent GPS monitoring data along thecentral longitudinal section, which is not open in thisperiod.
Another important tendency was recorded in themonitoring results. In mid-September, the water level of
the Three Gorges was raised for about 3 m,corresponding to this water level raising, thedisplacement velocity of SP1-5, SP1-6 and SP1-7
increased obviously, reflecting the influence of theimpoundment on the slope deformation.
6.

1m-depth ground temperature measurement
for groundwater veins

Figure 10 Principle of the 1m-depth ground temperature
measurement

Fig. 11 Groundwater veins distribution estimated from 1m ground temperature measurement

Takeuchi (1972) developed a method for theinvestigation of groundwater veins through 1m-depth
ground temperature measurement. This method is widely
applied in the practice of groundwater exploration inlandslide area, especially in Japan (Takeuchi 1996).

Figure 12 Column diagram of borehole SPZK-1 inBlock-1 of Shuping landslide

Figure 10 shows the principle of the 1m groundtemperature measurement for groundwater vein.

Comparing with the ground without water, the groundwith water always has a temperature similar with that of
the groundwater. Generally, groundwater temperaturedoes not change so much around a year. While, thetemperature in the ground without water is controlled by
the atmosphere temperature. It is higher thangroundwater in summer and autumn, and lower in spring
and winter. Through analyzing the temperature
distribution in an area, the distribution situation ofgroundwater vein can be estimated.
To detect the groundwater veins in the lower part of
the Shuping landslide, 1m-depth ground temperature
measurement was conducted. The measured area wasshown as a square in Figure 3. Figure 11 is the measured
results. From the ground temperature distribution, two
independent groundwater vein groups were estimatedexisting in Block-1 and Block-2. The exit of thegroundwater vein in Block-1 is lower that that in Block-2.
It is estimated that the groundwater veins No.8 and No.9
correspond to the muddy water seeped from Block-1.
To confirm the above estimation, and to explore thesliding surface, a borehole drilling was conducted atSPZK-1, as shown in Figure11. Figure 12 is the column
diagram of this borehole. The groundwater table wasfound at 8.8 m deep, and the sliding zone formed at thedepth between 66.7 and 75.9 m. The sliding zone
consisted of silty clay with 30% gravel. Scratches causedby sliding are rich in the zone.
7.

Summaries and conclusive remarks

Figure 13 Longitudinal section of the Shuping landslideThrough the GPS monitoring, crack displacement
measurements, extensometer monitoring along thelongitudinal section of Block-1, the deformation style ofthe Block-1 of Shuping landslide can be sketched as
Figure 13. Sooner after the impoundment of the water
reservoir, the toe part displaced downward faster than theupper part. In the current stage, one and half years after
the first impoundment, the slope deformation stylechanged. The displacement of the lower part almost
terminated while the upper part displaced downward
gradually, and compressed the toe part.
For the Shuping landslide, reactivating from an oldlandslide and with rich groundwater in it, the influencing
factors on the slope deformation is complicated. Fromthe half year monitoring with the extensometers, it isvery clear that the slope displaced soon after theimpoundment of the water reservoir. It is very importantto keep the monitoring continued especially during thenext stage of impoundment which will be conducted inJune 2006 (Water level will be raised from 139 m to 156m.). Also the influence of the rainfall on the slope
displacement can be analyzed in the next half year when
the water level is kept constant at the upcoming rainyseason.

Town supplied measurement results of the crack
displacement. The research fund from Sabo TechnicalCenter, Japan is highly appreciated.
ReferencesGan, Y.B., Sun, R.X., Zhong, Y.Q., Liao, S.Y. 2004.
Urgent investigation report on the Shuping landslide in
Shazhenxi town, Zigui County, Hubei Province (inChinese).
Takeuchi, A. 1972. Ground temperature measurement inlandslide area. Journal of Japan Landslide Society, 8(4):29-37, (in Japanese).
Takeuchi, A. 1994. Flowing groundwater investigation
by temperature measurement. Kokon Syoin Press (inJapanese).
Wang, F.W., Zhang, Y.M., Huo, Z.T., Matsumoto, T.,
Huang, B.L. 2004. The July 14, 2003 Qianjiangping
Landslide, Three Gorges Reservoir, China, Landslide,1(2): 157-162.
Zhang, YM, Peng, XM, Wang, FW, Huo, ZT, Huang BL(2004): Current status and challenge of landslide
monitoring in Three-gorge reservoir area, China. Proc.
of Symp. On Aapplication of real-time information indisaster management, JSCE, pp.165-170.
Zhang, Y.M., Liu, G.R., Chang, H., Huang, B.L., Pan, W.
2004.
Tectonic analysis on the Qianjiangping
landslide in Three Gorges Reservoir area and arevelation. Yangtze River, 35(9): 24-26 (in Chinese).

Acknowledgements
Deep thanks are given to Mr. Masahiro NAGUMO
in Kowa Co. LTD., Japan for donation of twoextensometers. The local government of Shazhenxiਛ࿖ਃጽ࠳ࡓ⾂᳓ᳰ࿾ၞߦ߅ߌࠆḖ᳓ߦࠃࠆ᮸ဝ࿾ߔߴࠅߩᄌേ᷹ⷰ෸߮⺞ᩏߦߟ޿ߡ᳴ ⊒ᱞ࡮₺ ഞノ࡮૒‫ޘ‬ᕶੑ࡮ᣂ੗႐౏ᓼ ࡮┻ౝ◊㓶 ࡮ᒛ ᬺ᣿ ࡮ᓄ イ᣿ ࡮㔥 ᔒứ ࡮㊄ ⛽⟲ ⁛┙ⴕ᡽ᴺੱᶖ㒐⎇ⓥᚲ
⥄ὼ࿾ਅ᳓⎇ⓥᚲ
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